M.-S. Cho et al. / Journal of Organometallic Chemistry 685 (2003) 99ꢁ
/106
105
(
0.030, 0.12 mmol) and N-Selectride (0.024 ml, 0.24
ether in various portions and dried under reduced
pressure at 50 8C for 1 day to yield 0.314 g (90% yield)
of beige solid (TGA ceramic residue yield: 64%).
mmol). The reaction mixture turned into deep green
immediately evolving hydrogen gas and was solidified
with dark green coloration after 4.5 h. After 1 day the
catalyst was inactivated by exposure to the air for a few
minutes. The reaction product was rinsed well with
diethyl ether in various portions and dried under
reduced pressure at 50 8C for 1 day to give 0.317 g
3.7. Crosslinking reactions of PPVS catalyzed by
Cp MCl /Red-Al (MꢀTi, Zr)
/
2
2
As a typical reaction, to a 100-ml Schlenk flask were
charged Cp TiCl (0.013 g, 0.053 mmol) and Red-Al
(91% yield) of pale yellow solid (TGA ceramic residue
yield: 79%).
2
2
(0.016 ml, 0.053 mmol) under nitrogen atmosphere, and
PPVS (0.35 g, 2.65 mmol) in 1 ml of toluene was slowly
syringed. The reaction mixture turned into deep brown-
ish green immediately evolving hydrogen gas. After 5
min, the reaction mixture was slowly heated up to 80 8C
and was solidified with brownish yellow coloration after
30 h. The resulting mixture was rinsed well with diethyl
ether in various portions and dried under reduced
pressure at 50 8C for 1 day to give 0.330 g (94% yield)
of pale yellow solid (TGA ceramic residue yield: 48%).
3
.4. Crosslinking reactions of PVS catalyzed by
Cp MCl /Super-Hydride (MꢀTi, Zr, Hf)
/
2
2
In a typical reaction, to a 100-ml Schlenk flask were
added Cp TiCl (0.030 g, 0.12 mmol) and Super-
Hydride (0.024 ml, 0.24 mmol) under nitrogen atmo-
sphere. The mixture was stirred at room temperature for
2
2
3
min. PVS solution (0.35 g/0.3 ml in toluene) was then
slowly injected. The reaction mixture turned into deep
green immediately evolving hydrogen gas and was
solidified with orange coloration after 5.5 h. The
catalyst was inactivated 24 h later by exposure to the
air for a few min. The reaction product was washed well
with diethyl ether in various portions and dried under
reduced pressure at 50 8C for 1 day to afford 0.314 g
Acknowledgements
This research was supported by the Korea Science
and Engineering Foundation (Project No. R01-2001-
000-00053-0; 2002).
(90% yield) of pale yellow solid (TGA ceramic residue
yield: 70%).
References
3
.5. Crosslinking reactions of PVS catalyzed by
M(CO) (MꢀCr, Mo, W)
/
[1] A.G. Evans, Ceramic and ceramic composites as high-tempera-
tures structural materials: challenges and opportunities, in: R.W.
Cahn, A.G. Evans, M. McLean (Eds.), High-Temperature
Structural Materials, Chapman & Hall, London, 1996.
6
As a typical reaction, to a 100-ml Schlenk flask was
added Cr(CO) (0.026 g, 0.18 mmol) under nitrogen
6
[
[
[
2] (a) Y.G. Gogotsi, V.A. Lavrenko, Corrosion of High-Tempera-
ture Ceramics, Springer, Berlin, 1992;
atmosphere, and PVS (0.35 g, 6.02 mmol) in 2 ml of
dioxane was then charged. The reaction mixture was
slowly heated up 80 8C in order to minimize the
(b) P.J. Jorgensen, M.E. Wadsworth, I.B. Cutler, J. Am. Ceram.
Soc. 42 (1959) 613;
(
c) I. Franz, W. Langheinrich, Solid State Electron. 14 (1971) 499.
sublimination of Cr(CO) and was solidified with light
6
3] (a) Gmellin Handbook of Inorganic Chemistry, eighth ed.,
Springer, Berlin (FRG), 1984, Supplement Volume B2.;
yellow coloration after 20 h. After 24 h, the resulting
mixture was rinsed well with diethyl ether in various
portions and dried under reduced pressure at 50 8C for 1
day to provide 0.340 g (97% yield) of light yellow solid
(
b) D.R. Messier, W.J. Croft, in: W.R. Wilcox (Ed.), Preparation
and Properties of Solid-State Materials, vol. 7 (Chapter 2), Marcel
Dekker, New York, 1982 (Chapter 2).
4] (a) J.A. Powell, L.G. Matus, in: G.L. Harris, C.Y.-W. Yang
(
TGA ceramic residue yield: 63%).
(Eds.), Amorphous and Crystalline Silicon Carbide, Springer,
Berlin, 1989;
3
(
.6. Crosslinking reactions of PVS catalyzed by Cp M
2
(b) National Research Council, Materials for High-Temperature
Semiconductor Devices, National Academy Press, Washington,
DC, 1995, Chapter 2.
MꢀCo, Ni)
/
[
5] (a) E. Fizer, R. Gadow, Am. Ceram. Soc. Bull. 65 (1984) 326;
b) Gmelin Handbook of Inorganic Chemistry, Springer, Berlin,
984 and 1986, Silicon Supplements B1 and B3.
The following procedure is the representative of the
crosslinking reactions with the Group 8 metallocene
Cp M (MꢀCo, Ni) catalysts. To a 100-ml Schlenk flask
(
1
/
2
[6] (a) S. Yajima, J. Hayashi, M. Omori, Chem. Lett. (1975) 931;
(b) S. Yajima, J. Iwai, T. Yamamura, K. Okamura, Y. Hayashi, J.
Mater. Sci. 16 (1981) 1349;
was added Cp Ni (0.023 g, 0.12 mmol) under nitrogen
2
atmosphere, and then, PVS solution (0.35 g/0.3 ml in
toluene) was slowly injected. The reaction mixture
turned into light green immediately evolving hydrogen
gas and was solidified with brown coloration after 45
min. The reaction product was washed well with diethyl
(
(
(
(
c) S. Yajima, Ceram. Bull. 12 (1983) 933;
d) S. Yajima, J. Hayashi, J. Omori, K. Okamura, Nature 261
1976) 683;
e) S. Yajima, Y. Hasegawa, J. Hayashi, M. Iimura, J. Mater. Sci.
13 (1978) 2569;